ABSTRACT
Availability of scientific research at high levels of evidence, provide an appropriate context for evidence-based nursing. This study aims to identify the levels of evidence of nursing theses and dissertations in type-one medical universities of Iran in a period of twenty years. This is a descriptive survey on 1810 nursing theses and 54 dissertations. The abstract and/or method section of the theses and dissertations during 1991-2010 was reviewed and then their levels evidence were determined by comparing these data with the table of evidence-based research assessment. Descriptive analysis on data was performed using SPSS-PC [v.16]. A large percentage of the theses [60.7%] and dissertations [92.6%] were at the 6[th] level of evidence. First and 5[th] levels of evidence were not seen in Msters Theses, and none of the 1[st], 4[th] and 5[th] levels of evidence was found in PhD dissertations. The lowest percentages [1.9%] of theses were situated at the 4[th] level. Only 7.4% of the dissertations were at the 2[nd] and 3[rd] levels of evidence. The trend of theses and dissertations changed into performing research at the 2[nd] and 3[rd] levels of evidence. The results revealed that the majority of theses and dissertations in all educational fields and faculties are at the lowest [6[th] level of evidence during the studied period. Thus, regarding the importance of evidence-based practice for increasing the quality of nursing care, investigating approaches to promote and improve the level evidence of nursing theses and dissertations is recommended